Ice cover on Lake Superior is largest in decades

DULUTH, Minnesota (KARE) -- Lake Superior is virtually icing over for the first time since 1996, thanks in large part to unyielding arctic air.

"This wasn't even a cold snap. It was just persistent cold for most of January and for most of December as well," Jay Austin, of the Large Lakes Observatory at the University of Minnesota Duluth, told KARE.

"This year is really very remarkable."

It's not just the sheer amount of ice on Lake Superior that's drawing so much attention, but the fact that it bucks the general trend of warming on the big lake in the past two decades.

Composite ice coverage maps generated by the US Navy and Canadian Ice Service show that nearly all of the lake's surface was 90 to 100 percent covered in ice by mid-February. A comparison with the same week in 2013, 2012, 2011 and 2010 show revealed that most of the lake was ice free, open water.

In February of 2009, almost half of the lake had iced over to the 90 to 100 percent level, but there was still a sizable area of open water even that year.

"Years like this are becoming less and less common with time, and years like 2012 when we had basically no open water ice whatsoever are becoming more and more common," Austin, an assistant professor of physics and lake temperature researcher, told KARE.

Of course, we're not talking about a solid sheet of ice from one end of the lake to another. It's constantly shifting and breaking up due to wind conditions.

"The wind is still capable of moving some of that shore ice out into the lake," Austin explained.

"And so one day Duluth will be completely socked in and the next day we'll have open water."